Internal pump for nuclear reactors
AssigneeHitachi, Ltd.
InventorIsamu Kadowaki
Life of this patent
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Abstract
A nuclear internal pump is disclosed in which a flywheel and a thrust disc acting as an auxiliary impeller are fixed on a motor shaft. Fixed orifices X and Y are formed respectively between outer circumference section at larger and smaller diameter sides of the thrust disc and larger and smaller diameter rings disposed to face the outer circumference section respectively, thereby to form a pressurized chamber between the two fixed orifices X and Y. The thrust disc is equipped with an axial thrust reducing device which has two sets of channels for circulating motor cooling water and for boosting the pressure in the pressurized chamber.
Claims6
An internal pump for a nuclear reactor, comprising:
- a pump unit disposed in a nuclear reactor pressure vessel, said pump unit including an axially extending pump shaft drivingly connected to a pump impeller, and
- a motor unit disposed in a motor casing joined to the pressure vessel and having a motor shaft coaxial with and connected to the pumpshaft, said motor unit including:
- a motor rotably driving the motor shaft,
- a flywheel fixed to the motor shaft at one axial side of the motor,
- a thrust disc fixed to the motor shaft at an axial side of the motor opposite the one axial side, said thrust disc serving as an auxiliary impeller, said thrust disc exhibiting a plurality of coaxial cylinder portions of different diameters including a bulging cylinder portion of large diameter and a constricted cylinder portion of smaller diameter than said bulging cylinder portion,
- a large ring housing section surrounding the bulging cylinder portion with a first fixed orifice formed between the bulging cylinder portion and the large ring housing section, and
- a small ring housing section surrounding the constricted cylinder portion with a second fixed orifice formed between the constricted cylinder portion and the small ring housing section,
- said ring housing sections and cylinder portions defining a pressurized chamber between the first and second fixed orifices.
Dependencies are inferred from the claim text.